thyroid-stimulating hormone test (TSH test), a thyroid function test in which thyrotropin (thyroid-stimulating hormone) is administered intramuscularly and the thyroid gland is monitored over time with scintiscanning or radioimmunoassays for a response or areas of decreased responsiveness. It is also used to monitor exogenous thyroid replacement. The test was formerly used for determining whether hypothyroidism was caused by thyroid gland failure or by deficiency in thyrotropin. Also called thyroid-stimulating hormone assay.
